Figure 2. Clinical utility of AD-RAI in MCI subjects. A 50-year-old man with 16-year education had complaints of impaired short-term memory for 4 years. Z-score in Trial 4 of HKLLT was -2.97 SD (≤ -1 SD, i.e. MCI). The average visual MTA rating score was 0 suggestive of non-AD (A). HV measures also suggested non-AD, with a normal raw HV of 7.25mL (> 6.07mL) and HF of 0.48% (> 0.41%). However, AD-RAI was 0.68 (> 0.5) suggestive of AD. Subsequent PIB PET (B) and T807 PET (C) confirmed PIB and T807 retention, respectively (red arrows). The final diagnosis of this subject was prodromal AD. Abbreviations: AD-RAI=Alzheimer’s disease resemblance atrophy index; MCI=mild cognitive impairment; MTA=medial temporal lobe atrophy; HKLLT=Hong Kong List Learning Test; SD=standard deviation; MRI=magnetic resonance imaging; HV=hippocampal volume; HF=hippocampus fraction; PET=positron emission tomography; SVD=small vessel disease.